Diazotype photographic material



Patented June 6, 1944 DIAZOTYPE PHOTOGRAPH) MATERIAL Waldemar Vanselow,

Dudley B. Glass, Rochester Eastman Kodak Arnold Weissberger, and N. Y., assignors to Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application August 5, 1943 v a SerialNo. 497,546

4 Claims. (01. 95-7) This invention relates to diazotype photographic materials. More particularly, it relates to diazotype copying materials wherein the light-sensitive compound is a diazo derivative ofan aminophenyl pyrrolidine having the general formula:

CHr-CHI UHr-CHr v wherein It represents a phenyl nucleus having the amino group in position para or ortho to N. In addition to the amino groups, R can also be substituted in one or more positions not occupied by the amino groups by monovalent s'ubstituents such as an alkyl group represented by methyl, ethyl, propyl, or butyl, for example, an alkon group represented by methoxy, ethoxy, propoxy, or butoiw, for example, a halogen, such as chlorine, bromine, or a sulphonic acid radical.

We have found that the diazo derivatives of the above described compounds are stable under all ordinary conditions, but decompose more or less completely on exposure to light. Since they are also capable of condensing with certain aromatic coupling components, as well as with their own decomposition products, in the presence of alkaline substances, to form fast azo dyes, we have found that'our diazovderivatives are excellent light-sensitive components in diazoWP P otographic copying materials. In the presence of selected coupling components on a suitable support, they have excellent keeping qualities under all ordinary conditions of storage. On exposure of such sensitized support to light behind a pattern such as a transparent photographic negative or positive, a line drawing, printed matter or other similar contrasty subject matter and subsequent alkaline processing, images are obtained which have permanent dark lines and tones in the unexposed sections contrasted to almost white or slightly gray or tan fields in the light exposed areas. The prints obtained show good contrast and have excellent keepin qualities.

The alkaline processing consists ordinarily of subjecting the exposed diazotype sheet to an atmosphere of ammonia vapors but it is also 1 possible to develop the image by means of dilute aqueous solutions of weak alkalies or alkylolamines such as triethanolamine or by means of steam in which case the sensitized coating must contain a suitable alkali incorporated therein. As willbe more fully apparent from the examples given, we can, prepare our new diazotype materials by a number of methods. For example, the base or support carrying or containing the light-sensitive compound or compounds 5 can be paper, cloth or a film such as prepared from cellulose nitrate, cellulose acetate, cellulose acetate-propionate, regenerated cellulose, and.

the like, a glass plate or sheet metal, the sensitizing substance being applied by coating. dipping, brushing, spraying, dusting or by any other means known to one skilled in the art and in accordance with the requirements of the particular support employed. 7

The sensitizing compounds can be applied from asolution containing one or more of our diazo compounds together with one or more selected coupling components and may also have present one or more stabilizing compoundsselected from the group including hydrochloric 2o acid, boric acid, tartaric acid, thiourea, and the like. Ordinarily, however, the light-sensitive compounds and the coupling compounds are dissolved in separate solutions and applied to the sheet material to be sensitized in sequence. The stabilizers are usually incorporated in th diazo salt solution. After each application, the sheet may be dried, if desired. Another modification is to add a thickening or emulsifying agent to the solution or solutions such as gelatin, polyvinyl alcohol, polyvinyl phthalate, cellulose acetate phthalate, gum tragacanth, a higher fatty acid 'glyceryl sulfate or other similar kind of substance. The solution concentrations of the sensitizing compounds can be varied within fairly wide limits, the preferred range "being up to 2% by weight of the diazo compound and about the same concentration of the coupling compound. Good results have also been obtained with concentrations as high as- 4% by 40 weight of the respective components. The stabilizers can also be varied within fairly wide limits of concentration.

It is an object of our invention, therefore, to

provide diazotype copying materials which combine the advantages of good stability, high degree of sensitivity to light and produce prints which are characterized by excellent keeping qualities, good sharpness and contrast. 7 a

The heterocyclic intermediates and sensitive 5o diazo compounds were prepared by the following methods.

1. Pyrrolidine.-Prepared by the method of Signaigo and Adkins, J. Am. Chem. Soc. 58, 709 (1936).

2..1-(p-nitr0phenyl) -purrolidine.-Qne mole phenyl)-pyrrolidine was dissolved in 100 cc. of

absolute alcohol and hydrogenated'at a temperature of 60 and a hydrogen pressure of 45 lbs.

per sq. inch in the presence of g. of Raney. nickel.

The reaction mixture was cooled, filtered from the catalyst and treatedwith a solution of 3 cc. of concentrated sulfuric acidin cc. of water. The precipitate was removed by filtration and dried in air. There resulted 9.7 g. (75 per cent) of the desired product which can be purified further by recrystallization from 100 cc. of 75 per cent aqueous acetic acid.

4. 1 (3'-methyl-4'-nitrophenyl) -pyrrolidine. Prepared from 3-iodo'-6-nitrotoluene (1 mole) and pyrrolidine (2 moles) by procedure used for the preparation of l-ip-nitrophenyl) -pyrr'olidine, M. P. 86-88".

5. 1-(4'-amino-3'-methylphenyl) pyrrolidine hemisulfate.Prepared from 1-(3'-methyl-4'-nitrophenyD-pyrrolidine (10.7 g.) by the procedure used for the preparation-of l-(p-aminophenyl) -pyrrolidine hemisulfate dihydrate. The

roduct was purified by recrystallization from 80 per cent ethanol.

The invention is illustrated further by the following examples:

Example-1 pr x ly 1.! grams of l-(p-aminophenyl) -pyrrolidine hemlsulfate. F

CHr-CHg was diazotized in the usual manner. The final volume of the diazonium compound solution was 100cc. The white paper was bathed or coated with the above solution and then with-a 1 per cent solution of p-naphthol. dried, exposed, and processed dry in ammonia in the customary manner. A reddish-brown image on a very pale tan or nearly white field was obtained. A sixday incubation test at 48 /2? C. of the material before processing caused the field to darken to k a tan upon subsequent exposure and processlng.

Example 2 exposed sensitized paper and the prints obtained therefrom showed considerable improvement over those of Example 1.

Example 3 Approximately 0.5 gram of 1-(4'-amino-3- methyl phenyl) -pyrrolidine hemisuifate,

CH: Clix-CE;- l N P111111?! was diazotized in the usual manner so as to have cc. of solution.

To this diazonium salt solution was added a 10 cc. portion of a stabilizer stock solution consisting of 2 cc. of concentrated I-lCl, 2.0 grams of boric acid, 4.0 grams of tartaric acid and 0.2 gram of thiourea per 100 cc. volume.

The white paper was bathed or coated with the above solution and then with a 1 percent solution of fi-naphthol, dried, exposed and processed dry in ammonia in the customar manner. A pale purple image on a nearly white field was obtained.

- While our invention has been illustrated more particularly in connection with fi-naphthol as the coupling component, it will be understood that other coupling components belonging to the hydroxy aromatic group of compounds are likewise included within the scope of the invention. For a detailed description of such coupling components, reference can be made to Welssberger and Vanselow U. S. Patent No. 2,298,444, granted October 13, 1942.

We claim:

1. A light-sensitive diazotype material comprising a light-sensitive diazo derivative of a compound having-the general formula:

wherein It represents a benzene nucleus.

2. A light-sensitive diazotype material comprising a light-sensitive diazo derivative of a compound having the general formula:

prising a light-sensitive diazo derivative of a compound having the general formula:

. CH: CHa-CH:

NGNH. Hr-Cl warmnuan vausmow. ARNOLD mm. DUDLEY a. cuss. 

